Yes, you can use full URL mask, just don't forget to check the corresponding option.

ASF > option > page 2 : Use the current website URL to verify the filter's domain if the hosted domain doesn't match.

And be sure to use the latest beta available on the Download page/beta (ASF 1.0.1 is only watching for the domain, not the full URL).

It will first check the domain, if it doesn't match with the domain only, it will use the full current website URL (not the full hosted file URL).
I will add the option to use the downloaded file URL on a later release.

Edit :
Update after 1.0.2r86 :

Use current Website URL has been replace with more options : file's domain only, file's URL, tab's domain and tab's URL.
Select the order you want them to be used.

By default, the Domain Test Order is set to 1,5:
First it tests the file's domain name, if it doesn't match then it test the full text written in the current opened tab's URL.

If you want to filter based on the file's URL http://domain.com/a/
Then try 1,2
if you want to filter based on the visited website URL, then try 1,5

You can have more than two, for example : 1,2,5
Or only one : "2" as it also contains the domain's name, but you can't create other filters using regular expression based only on the domain name if you use "2", so it's better to always keep "1", so use: "1,2".